One type of prior electrical assembly includes a printed circuit board ("PCB") on which electrical connectors and devices are mounted. The electrical connectors and devices are typically assembled on one side of the printed circuit board by a prior surface mounting process. The electrical connectors are typically used to connect the PCB to other electrical components or PCBs.
A typical prior art surface mounting process for a PCB assembly includes the following three steps: a solder screen printing step, a component placement step, and a solder reflow step.
During the solder screen printing step (also referred to as a solder screening operation), a controlled volume of solder paste is deposited onto surface mount pads arranged in a land pattern on the PCB. The solder deposition is accomplished by drawing solder paste over a metallic stencil (or screen) with openings for the surface mount pads on the PCB. The solder paste is pushed through the openings of the stencil with a squeegee. After solder deposition is complete, the stencil is raised and removed from the PCB, leaving a print of solder paste on the surface mount pads of the PCB.
An electrical connector, for example, is then placed on top of the printed solder paste. This placement is typically done by dedicated surface mount placement equipment, by customized robotic arms, or by hand. The leads of the connector must be accurately aligned with the print of solder paste and with the surface mount pads.
Once the electrical connector has been properly placed, the solder reflow step (also referred to as the solder reflow operation) is initiated. The populated PCB passes through a series of heated areas, wherein the temperature of the solder paste is carefully elevated. Once the temperature reaches the melting temperature of the solder paste and the solder becomes liquified, the connector bonds to the PCB after cooling.
Typically the prior art surface mounting process is used for electrical connectors, components, and devices.
The technological push for smaller, lighter, and thinner PCB assemblies has led to the creation of a new family of connectors. The new connectors are referred to as straddle-mount connectors. A straddle-mount connector typically mounts on an edge of a PCB and electrically connects to both sides of the PCB.
One disadvantage of the prior surface mounting process is that the mounting of a straddle-mount connector onto the PCB typically requires the connector to be hand soldered to the PCB or requires the use of laser equipment to make the connection. This is because the solder screen printing operation of the surface mounting process is typically only performed on one side of the printed circuit board at a time. Given that the straddle-mount connector must be mounted on both sides of the PCB in one surface mounting process, the solder screen printing operation poses difficulties with respect to the use of the straddle-mount connectors.
Furthermore, given that the stencil must be flush with the surface of the PCB, connectors are precluded from being presented onto the surface of the printed circuit board during the solder screen printing operation.